1. Field of the Invention:
The field of invention relates to circular power saws, and more particularly, circular blades for such saws. Specifically, the invention is direct to the teeth on such circular blades.
Circular power saws include portable, motor-driven circular power saws, bench saws (often referred to as "table saws" or "circular saws"), and radial-arm saws. Such saws are used to cross cut, rip cut, and cut on a diagonal. Additionally, in bench saws, for instance, bevel cuts can be made when the blade is tilted.
Operation and use of such circular power saws are well known.
The blades of such saws are circular disks having blades of for instance from 41/2" in diameter for, for instance, portable trim saw blades to 71/2 to 10" in blade diameter for bench saws and radial saws. In some instances, radial arm saw blades may extend to 12" to 14" and beyond. The driving shafts, or arbors of the saw rotate in the same direction at all times when the saw is turned on, and the saw blades are designed to cut in one direction only, so that the saw blade must absolutely be mounted to rotate in the right direction. Extreme care must be taken to insure that the blade is affixed to the rotating shaft of the saw so that the blade rotates in the proper direction.
2. Description of the Prior Art
Prior art circular saw blades have teeth which are of hook shape inclined toward the direction of rotation. The teeth are set in the well known fashion to provide a kerf which yields ample clearance to prevent binding. The teeth are generally in the form of the conventional crosscut type of tooth, which, although not completely efficient in a ripping action, nevertheless performs adequately for its intended purpose.
A problem with the prior art circular power saw blade is that it cuts only in one direction of rotation of the blade. If the blade is attached to the saw with the teeth projecting in the wrong direction, a cut is not possible since there is a burning effect. Hence, when the saw becomes dull from cutting in its intended direction, it cannot be used by reversing the blade to achieve a continued life.
Additionally, a blade mounted to rotate in the wrong direction can present a safety hazard since the saw can bind, or jam, and then jump under the motor driving force.
In summary, the prior art power circular saw blade is only usable when rotated in one direction, and is ineffective and unusable, and even unsafe, when rotated in the opposite direction.
Some circular power saw blades are specially hardened to give relatively long life, but cannot be resharpened in a conventional fashion. Relatively low cost blades, however, makes disposal practical. Others can be resharpened with a file, on a job location, by a mechanic knowledgeable in the art.